Positive Splits for Marathons? The Answer May Surprise You

Positive splits for marathons is a topic that scares many runners, but it need not do so.

First, it helps to understand what a split is. Second, it’s important to be able to identify a negative split and a negative-split race. Third, it’s crucial to know when negative-split races make sense. Fourth, you should recognize positive-split marathons and why people recommend negative-split ones. Fifth, you should learn how common positive-split marathons are among elite runners. And, sixth, you can learn what to do about your own positive-split marathons.

What is a split?

Think of splitting a race or training run into two or more equal-distance segments. A “split” refers to the time required to complete one of those segments.

A track coach will press the split button on a stopwatch to get the duration of a segment. Often, a stopwatch will freeze the split-duration display while total timing continues.

For example, a coach or runner might want the split durations for:

• Every 100-meter segment in a 400-meter race;
• Every 400-meter segment in a 1,600-meter race;
• Every kilometer segment in a 5,000-meter race.

A word about words

Most people use the word “time” as their substitute for “duration”. They do this even though these two words have different meanings. I have a linguistic hypothesis that helps to explain this substitution. I call it my “Devolution toward Simpler” hypothesis.

Anyway, what this means is that you usually will see “split time” where people mean “split duration”. So, I’ll use “time” where I mean “duration” for the rest of this discussion.

What is a negative split?

The concept of a negative split comes from the track world.
[Tweet “A negative split means that a split time is smaller than the split time that preceded it.”]

Consider Galen Rupp, an Olympic silver-medalist, at the 2014 Boston University Multi-Team Meet. Running the men’s 5000-meter race in 13:01:26, he set a new American indoor record.

And, Rupp did it with negative splits from one mile to the next. Here were Rupp’s mile splits:

• Mile 1 in 4:14
• Mile 2 in 4:12
• Mile 3 in 4:04

His split times decreased as he completed each mile:

• Mile 2 vs. Mile 1: -2 seconds
• Mile 3 vs. Mile 2: -8 seconds

What is a negative-split race?

Galen Rupp not only had negative mile-splits in his record-setting 5,000-meter race. A “negative-split race” is another way to describe what he achieved. This refers to a race split into only two equal-distance segments — two halves, in other words.
[Tweet “A negative-split race is one that someone runs faster in the second half than in the first half.”]

For a simpler example, consider a woman in an 800-meter race. Suppose that she ran the first 400 meters in 59 seconds. And, suppose that she ran the second 400 meters in 58 seconds. Then she ran a negative-split race.

When do negative-split races make sense?

Negative splits are common in 100-meter races. Runners must react to the sound of the starter gun and get up to speed from a dead stop. At the sound of the gun, they shoot out of the blocks and continue to pick up speed as they run toward the finish line.

It is no surprise that many 100-meter runners are slower in the first 50 meters than in the second 50 meters. For example, consider Usain Bolt’s 100-meter world record (WR) of 9.58 seconds. Here are the durations of his two 50-meter segments:

• 5.47 seconds from 0 to 50 meters
• 4.11 seconds from 50 to 100 meters

Crossing the 0-meter line from a dead stop is different from crossing the 50-meter line at a sprint. As an example, consider sprinter Usain Bolt again. He set a world record of 19.19 seconds in a 200-meter race in Berlin in 2009. Here are the durations of those four 50-meter segments:

• 5.60 seconds from 0 to 50 meters
• 4.32 seconds from 50 to 100 meters
• 4.52 seconds from 100 to 150 meters
• 4.75 seconds from 150 to 200 meters

Bolt took 9.92 seconds to run 100 m from 0 meters to 100 meters. But, he took only 8.84 seconds to run 100 m from 50 meters to 150 meters. So, a flying start can be faster than a dead-stop start.

Now, consider the effects of the dead-stop start in a 400-meter race or an 800-meter race. The longer the race, the less effect it has on someone getting a negative-split race. Yes, entering a segment from a dead stop will make that segment slower than one entered with a flying start. But, as you can see in the fourth 50-meter segment of Bolt’s WR 200-meter race, fatigue hits even the best.

What is a positive-split marathon?

A positive-split race is the complement to a negative-split race. A positive-split race is one in which the duration of the second half is longer than the duration of the first.

So, …
[Tweet “A positive-split marathon means taking more time to run the second half than to run the first half.”]

Why do people recommend negative-split marathons?

Here is marathon-training advice that I saw online in early 2015:

“We have stressed each week the importance of running your long runs practicing a negative split. We have continued to stress this because the facts will show that every world record from 1500 meters to the marathon has been set running negative splits [emphasis added] – running the first half of the race slightly slower than the second half.”

This discussion is about marathons, so let’s ignore the claim about shorter distances.

At this writing — in early 2017 — the above claim about marathon world records is incomplete.

• Yes, Dennis Kimetto set the latest world record (in 2014) with a negative split.
• But, Wilson Kipsang set the previous world record (in 2013) with a positive split.
• And, Patrick Makau set the world record previous to that one (in 2011) with a positive split.

[Tweet “Two of the last three marathon world records were set with POSITIVE splits!”]
Put another way, …
[Tweet “There is NOT a consistent pattern of NEGATIVE-split world-records among marathons!”]

In spite of these records, many coaches and runners recommend negative-split marathons. I suspect at least three causes:

• People are not aware of how common positive-split marathons are among elite runners.
• The latest marathon record involved a negative split, and the recency effect is in play.
• People may come from the track world, where negative-split races can make sense.

How common among elite runners are positive splits in marathons?

I found split data for seven of the most recent eight world-record setters through 2014. Here is how the top ten males performed in those seven world-record-setting marathons:

• 2014: Eight of ten ran positive splits.
• 2013: Ten of ten ran positive splits.
• 2011: Ten of ten ran positive splits.
• 2008: Seven of ten ran positive splits.
• 2007: Eight of ten ran positive splits.
• 2003: Eight of ten ran positive splits.
• 1999: Eight of ten ran positive splits.

So, only 11 of 70 top-ten males ran negative splits. Put another way, more than 84% of the top-ten males in those seven marathons ran positive splits!

If you look only at the three most recent world-record-setting marathons,
[Tweet “>93% of the top-ten males in the latest three world-record-setting marathons ran POSITIVE splits!”]

So, what should I do?

If your marathons are much slower in the second half than in the first, then, yes, you may be starting too fast.

But, if you are otherwise getting positive-split marathons, then enjoy them!

• You are in good company among elite runners.
• Even non-world-record-setting marathons can expose the negative-split myth.

[Tweet “Ignore the popular advice about negative-split marathons. Be happier; run your own race instead!”]

What next?

By letting go of feeling compelled to get negative splits in your marathons, you will be a happier runner.

To raise your happiness in other ways, check out Gratitude Power for Runners and Walkers. Happiness requires gratitude. This book will help you to build a rewarding daily habit of gratitude.

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Image Credit: Pixabay